The design and kinetostatic modeling of 3PPR planar compliant parallel mechanism based on compliance matrix method.

Compliant Parallel Mechanisms (CPMs) are widely used in micro/nano-positioning systems. In recent years, CPMs with a large travel range (≥1 mm) have been getting increasing attention. In this paper, a 3 Prismatic-Prismatic-Revolute (3PPR) planar CPM with a motion range of 5 mm × 5 mm × 5° is designed. The mechanical structure is characterized by the application of three joints based on a compliant four-bar mechanism, which guarantees the motions along/about the specific axes to improve motion accuracy. A double blade rotary pivot is served as a revolute joint to decrease the drift of pivot and produce a large rotation range without loss of compactness. The compliance matrix method is implemented to kinetostatic modeling, and the input coupling effect, which is always neglected or modeled complicatedly in 3-Degree-of-Freedom planar CPMs, is involved with the principle of superposition. The feasibility of the mechanical design and the accuracy of the developed kinetostatic model are validated by finite element analysis and experiments, respectively. The results indicate that the modeling method based on the compliance matrix method is concise, effective, and accurate, and can be extended to other more complicated CPMs.